A variety of therapeutic treatments are available for inducing bone growth at a desired site in a patient. Examples of such therapeutic treatments exist in the field of spinal surgery, including a variety of spinal fusion procedures. Illustratively, in posterolateral fusion procedures, bone growth is induced to fuse transverse processes of adjacent vertebrae, typically in the lumbar spine. In posterolateral fusion, the surgical approach to the spine is from the back, often through a midline incision. A bone graft harvested from the iliac crest of other donor zones of the patient is laid out in the posterolateral portion of the spine. Alternatively, allograft or synthetic bone graft material may be used. The back muscles that attach to the transverse processes are elevated to create a bed upon which to lay the bone graft. The back muscles are then laid back over the bone graft, creating tension to hold the bone graft in place.
A shortcoming of present posterolateral spinal fusion methods is the reliance on muscle tension or other inadequate means for maintaining bone grafts in place between transverse processes. This is especially so when the bone graft is presented as bone chips, granules or powders which can migrate out of the posterolateral portion of the spine over time. The present invention addresses the problem of bone graft containment and undesired bone graft migration from sites in a patient where bone growth is desired.